The present invention relates to the field of digital communications. In particular the present invention discloses a broadband digital broadcast system for broadcasting digital information to a very large number of subscribers.
The Internet has become a major source of news and information for very large numbers of people. In particular, millions of Internet users browse the World Wide Web (WWW) to obtain HyperText Markup Language (HTML) documents using the HyperText Transport Protocol (HTTP). Many people now receive more news and information from the Internet WWW sites than from traditional information sources such as television. The WWW portion of the Internet is an excellent medium for news and information since the WWW Internet sites can provide information to users on-demand. Specifically, Internet users can immediately request the exact information they are interested in when ever they wish from WWW Internet sites.
However, the Internet WWW system news information does suffer from a number of deficiencies. One serious problem is that the limited bandwidth of most Internet connections severely limits the amount of information delivered. Most Internet users access the Internet through a dial-up modem at speeds of 56 kps per second or less. With such limited bandwidth, most Internet based WWW sites only deliver text and static images. When video information is delivered through 56K Internet connections, the video information is compressed so heavily that only small low-resolution video images are delivered at a low frame rate.
To improve upon the performance of the Internet, many telecommunication providers are now offering high-bandwidth connections for the xe2x80x9clast milexe2x80x9d to an Internet user""s residence. Cable television providers are now offering cable modem Internet service that use cable television wiring to deliver broadband Internet service. Similarly, telephone companies are rolling out Digital Subscriber Line (DSL) services that provide broadband Internet service. Although these broadband data connections provide additional bandwidth, such broadband connections only address the xe2x80x9clast milexe2x80x9d bandwidth problem associated with sending rich multi-media information across the internet. Many other problems will continue to exist.
One problem of delivering rich multi-media information across the Internet is that there are no standard quality-of-service guarantees for Internet Protocol data traffic. All Internet Protocol traffic is delivered on a best effort basis such that Internet Protocol packets are often dropped. Due the rapid uncontrolled growth of the Internet, many severe Internet xe2x80x9ctraffic jamsxe2x80x9d have occurred at large Internet peering point such as MAE-East and MAE-west. Thus, even if a user has a broadband connection between his residence and his Internet Service Provider (ISP), there is no guarantee that the connection between the Internet Service Provider (ISP) and a desired Internet media server will provide the bandwidth necessary for a rich multimedia stream.
Another problem with attempting to deliver rich multi-media information across the Internet is the point-to-point nature of Internet communication. Most Internet communication occurs in a unicast manner wherein a unique communication connection is established between each information server and each Internet client. Since each Internet client requires its own connection, the bandwidth requirement for serving information grows proportionally with the number of Internet clients being served. Furthermore, each Internet client that requests service adds additional load to the server systems that serve information. To serve rich multimedia information to a large number of a client systems, a large powerful server farm is required. It is therefore quite expensive.from the server end in both communication costs and computer costs to serve large amounts of rich multi-media information.
Due to the above-described problems associated with Internet delivery of multimedia information, the Internet will largely remain a text and static image based information source. It would be desirable to provide a multimedia rich information system that is similar to the Internet in terms of on-demand access of interesting information but without the bandwidth problems associated with the Internet network system.
The present invention discloses a broadband data broadcast system that allows rich multimedia content to be delivered to the computer and information appliance systems of limitless numbers of subscribers. The broadband data broadcast system operates by multiplexing a plurality of multimedia rich digital information streams together at a centralized data broadcast center. The data broadcast center then broadcasts the multiplexed digital information stream on broadcast media such as satellite broadcasts, radio frequency broadcasts, or television broadcasts. A large number of receiver systems receive the broadcast signal and demodulate the broadcast signal to retrieve the multiplexed digital stream. The receiver system extracts a subset of digital information streams that the particular receiver system""s owner has designated are of interest. The receiver system may then output the interesting digital information streams to a display system or caches the interesting digital information stream for later access.
Other objects, features, and advantages of present invention will be apparent from the company drawings and from the following detailed description.